The invention is directed to natural oxide or silicate fillers modified with organosilicon compounds, a process for their production and their use in vulcanizable rubber mixtures.
It is known to treat oxide surfaces with organosilicon compounds in order to improve the bond between oxidic filler and organic polymers of the most different chemical composition through this pretreatment and accordingly to improve the reinforcing properties of the filler.
For example, for this purpose the organosilicon compound can be dissolved in an organic solvent and this solution treated subsequently, e.g., with clay, Papelos, U.S. Pat. No. 3,227,675, the entire disclosure of which is hereby incorporated by reference and relied upon.
It is known from Iannicelli, U.S. Pat. No. 3,567,680, the entire disclosure of which is hereby incorporated by reference and relied upon, to modify kaotin suspended in water with mercapto and aminosilanes. The organosilicon compounds concerned, however, are watersoluble in the amounts needed for the modification so that even in this case the treatment of the filler is carried out from a solution.
The problem of the invention was to find oxidic or finely divided oxidic or silicate fillers modified with water insoluble organosilicon compounds, which are compatible with rubbers and a process for their production which despite the water insolubility can be worked in aqueous phase without a solvent.